The aim of the paper is to present classification of inconsistencies in business processes using aspect taxonomy approach. On the basis of an in-depth literature review a set of criteria for the classification of sources of inconsistency has been submitted. The proposed classification of inconsistencies synthesizes aspects representing the critical success factors of BPM implementation and the aspect of infrastructure and technological capacity. Recent, experimental findings related to the presented issue have been presented in the empirical part of the paper. (original abstract)